JP2003140362A - Strengthening method of resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the etching durability of resist pattern and to suppress a shrinkage caused by SEM observation. SOLUTION: A wafer substrate 1 on which a prescribed resist pattern 2 is formed is immersed into a solution 10 in which an organic material 11 is dissolved. Thereby, the organic material in the solution is introduced into holes 3 of the resist pattern. In general, carbon contributes to the improvement of etching durability of the resist film and, therefore, the etching durability of the resist pattern 2 is improved. In addition, by introducing the organic material 11 into the holes 3, a shrinkage caused by electron beam irradiation on SEM observation is also suppressed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to etching and SE.
The present invention relates to a technique for improving resistance of a resist pattern to observation by M (scanning electron microscope).

[0002]

2. Description of the Related Art With the recent progress in miniaturization of semiconductor devices, the wavelength of exposure light in the process of forming a photoresist pattern is becoming shorter. For example, the minimum dimension is 130 nm
In the following resist pattern formation, ArF (193 nm) is used as an exposure light source.

The material of the resist is, because of its resolution,
It is necessary that the used film thickness has a transparency of about 50% or more with respect to exposure light. Acrylic, methacrylic, and COMA are used as the polymer of the resist material for ArF satisfying the conditions.
(Cyclo-Olefin Maleic Anhyd
Ride) system, Cyclo-Olefin system, and
The mixed system etc. are mentioned. FIG. 7 is a diagram showing an example thereof, (a) is a metallic system, and (b) is a COMA system.
And (c) are polynorbornene-based materials, respectively.

Although these polymers have high transparency,
There is a problem that the etching resistance is low. This problem is important because the resist pattern must maintain its shape and dimensions during etching. As a measure against that problem, for example, in the case of acrylic type, methacrylic type,
As shown in FIG. 7A, a protective group having a high etching resistance is provided on the side chain of the polymer. However, since the protective group generally has a large size, when a resist film is formed from a resist material provided with a protective group, the entanglement of polymers becomes rough and the film becomes porous.

Further, the main chain of the COMA-based material has a complicated structure, and since the molecular weight of the monomer is large, the number of monomers in the polymer is small and the termination is large.
Therefore, a resist film made of a COMA-based material as well as an acrylic-based material is also porous. Thus, A
The resist film for rF is porous, which causes problems such as deterioration of etching resistance and shrinkage of the resist pattern due to electron beam irradiation during observation by SEM.

[0006]

Problems to be Solved by the Invention FIGS. 8 (a) to 8 (d)
FIG. 4A is a diagram for explaining the problem of the conventional ArF resist, and shows the result of etching the oxide film substrate using the ArF resist as a mask. Among these, (a) shows the case where the pattern is not formed on the resist. Further, (b) to (d) show the state of the resist immediately after the hole pattern is formed in the resist and the oxide film substrate is etched using the hole pattern as a mask. Ratio of 1:
The figure shows the case of 4: 1, 2: 1, and 1: 1. As can be seen from these figures, the narrower the hole spacing, the greater the damage to the resist due to etching.

Similarly, FIGS. 9A to 9C also show the conventional Ar.
FIG. 4 is a diagram for explaining the problem of the F resist,
The result of etching the oxide film substrate using the resist for a mask as a mask is shown. Here, the state of the resist is shown immediately after the resist having a rain pattern is formed and the oxide film substrate is etched using the resist as a mask.
(C) shows a line pattern width of 0.30 μm,
The case where the thickness is 0.20 μm and 0.14 μm is shown.
As can be seen from these figures, the smaller the line width, the greater the damage to the resist due to etching.

From these results, it can be said that the finer the shape of the resist pattern, that is, the smaller the dimension of the resist, the greater the damage due to etching using the resist pattern as a mask. FIG. 10 is a diagram for explaining the relationship between the dimensions of the resist and the damage caused by etching.
Reference numerals 100a and 100b denote resists formed on the wafer substrate 110, and 101 denotes the resist 100a.
And 100b are used as masks to schematically show the influence of plasma for etching the wafer substrate 110. As shown in this figure, the resist 100a having a relatively large dimension (for example, a resist pattern having a wide hole interval or a resist pattern having a wide line width) is not damaged by the plasma to reach its central portion, and is damaged to the central portion. Since there is a portion 102 that is not subjected to the damage, the resist damage is not fatal. On the other hand, in the resist 100b having a small size, plasma damage reaches the central portion of the resist 100b, which may cause fatal damage to the resist. Furthermore, resist 1
Since the central portion of 00b will be damaged from both side surfaces, it is considered that the resist damage is accelerated.

Further, as described above, the resist for ArF is porous, and the minute voids deteriorate the etching resistance of the resist. FIG. 11 is a diagram showing experimental data for comparing the amount of holes in the resist for ArF and the resist resist for KrF. In this experiment, A
Ar was injected into each of the rF resist and the KrF resist. When Ar is injected into the resist, a part of the side chain of the polymer forming the resist is broken by the energy, a part of the side chain is re-crosslinked, and a part of the side chain of the polymer becomes a gas to escape from the resist film. Therefore, shrinkage occurs in both the ArF resist and the KrF resist. Figure 1
1 shows the relationship between the line width and the shrinkage amount in the resist of line pattern, the solid line is the experimental result for the ArF resist, and the broken line is the experimental result for the KrF resist. In this figure, the shrinkage amount is expressed by the dimension, and thus the shrinkage amount increases as the resist line width increases. The resist for ArF is K
It is observed that it shrinks more than the resist for rF. From this result, it can be seen that the ArF resist has a structure having more holes.

FIG. 12 is a diagram showing the change in the width of the resist depending on the number of times of observation by SEM. In this figure, the horizontal axis indicates the number of observations by SEM, and each observation time is 120 seconds. Further, the vertical axis shows the measured value of the resist width by the observation. Usually, in SEM observation, an acceleration voltage of 800 V is used.

The solid line 110 and the broken line 111 in FIG.
The figure shows the case where the ArF resist and the KrF resist are observed at an acceleration voltage of 800 V, respectively. It can be seen that the ArF resist has a significantly reduced size as the number of observations increases as compared with the KrF resist. From this result, it can be seen that the ArF resist has a structure having more holes.

In order to avoid the problem of resist shrinkage associated with SEM observation, it is conceivable to lower the acceleration voltage. A solid line 120 and a broken line 121 in FIG. 12 show the states when the ArF resist and the KrF resist were observed at an acceleration voltage of 300 V, respectively. From this figure, it can be confirmed that the contraction of the resist can be suppressed by decreasing the acceleration voltage. But,
Reducing the accelerating voltage is not practical because it sacrifices the observing ability of the SEM.

Further, these problems are problems not only in ArF resists but also in many resists having a porous structure.

The present invention has been made to solve the above problems, and improves the etching resistance of a resist pattern formed on a wafer, and at the same time, SEM.
It is an object of the present invention to provide a method for strengthening a resist pattern that can suppress shrinkage due to observation.

[0015]

A method for strengthening a resist pattern according to claim 1 is a method for strengthening a porous resist pattern having holes inside, wherein (a) the resist pattern is formed on a wafer. And (b) introducing a predetermined introduction product containing at least carbon into the holes of the resist pattern.

A resist pattern strengthening method according to a second aspect is the resist pattern strengthening method according to the first aspect, wherein the introduced substance is an organic substance, and the step (b).
Includes a step of immersing the resist pattern in a solution of the organic substance.

The resist pattern strengthening method according to claim 3 is the resist pattern strengthening method according to claim 1, wherein the introduced substance is an organic substance, and the step (b) is performed.
Includes a step of applying the organic material solution to the resist pattern.

The resist pattern strengthening method according to claim 4 is the resist pattern strengthening method according to claim 2 or 3, wherein the resist pattern is formed of a chemically amplified resist, and the step of (A)
However, the method further comprises exposing the chemically amplified resist to light, and the solution of the organic substance contains a cross-linking material that bonds the resist pattern and the organic substance using an acid as a catalyst.

The resist pattern strengthening method according to claim 5 is the resist pattern strengthening method according to claim 1, wherein the introduced substance is an organic substance, and the step (b) is performed.
Includes the step of exposing the resist pattern to the vapor of the organic substance.

A resist pattern strengthening method according to a sixth aspect is the resist pattern strengthening method according to any one of the second to fifth aspects, wherein the organic substance is a low molecular weight compound. To do.

A resist pattern strengthening method according to a seventh aspect is the resist pattern strengthening method according to any one of the second to sixth aspects, wherein the organic substance is a phenol. To do.

The method for strengthening a resist pattern according to claim 8 is the method for strengthening a resist pattern according to claim 1, wherein the introduced substance is a gas of an organic substance or an inorganic carbon compound, and the step ( b) includes a step of exposing the wafer on which the resist pattern is formed to the gas atmosphere and then increasing the pressure of the gas.

A resist pattern strengthening method according to a ninth aspect is the resist pattern strengthening method according to the first aspect, wherein the introduced substance is a substance serving as an ion source, and the step (b) is And a step of ion-implanting the introduced substance into the resist pattern.

A resist pattern strengthening method according to a tenth aspect is the resist pattern strengthening method according to any one of the first to ninth aspects, further comprising (c) after the step (b). And a step of irradiating the resist pattern with an electron beam.

The method for strengthening a resist pattern according to claim 11 is the method for strengthening a resist pattern according to any one of claims 1 to 9, further comprising (d) after the step (b). And a step of implanting ions into the resist pattern.

A resist pattern strengthening method according to a twelfth aspect is the resist pattern strengthening method according to any one of the first to eleventh aspects, wherein the step (b) is performed.
However, by adjusting the type and amount of the introduction,
The method is characterized by including the step of adjusting the dimensions of the resist pattern.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION <Embodiment 1> In the present embodiment, the resist is strengthened by introducing an organic substance into the minute pores of the porous resist. Hereinafter, a method of strengthening the resist according to this embodiment will be described.

First, a predetermined resist pattern is formed on the wafer substrate. After that, the organic substance in the solution is introduced into the holes of the resist pattern by immersing the wafer on which the resist pattern is formed in the solution (for example, a working process equivalent to dip development). FIG. 1 is a schematic diagram showing a state in which a wafer is immersed in a solution in which organic substances are dissolved. In this figure, 1 is a wafer substrate, 2
Is a resist pattern formed on the wafer substrate, and 3 is a hole in the resist pattern 2. Also, 10 is
A solution in which an organic substance introduced into the holes 3 of the resist pattern 2 is dissolved, and 11 indicates the organic substance.

Through this process, the solution 10 permeates the holes 3 of the resist pattern 2 and the organic substance 11 is introduced. FIG. 2 is a schematic diagram showing a state in which the organic substance 11 is introduced into the holes 3. It should be noted that in this figure, for the sake of simplicity of explanation, each hole 3 has a 1
Although one organic substance 11 is illustrated, a plurality of organic substances 11 may actually be introduced into one hole 3.

The process for introducing the organic substance 11 into the holes 3 of the resist pattern 2 is not limited to this. For example, low speed spin coating at 0 to several tens rpm and subsequent spin stop (for example, paddle). The solution 10 in which the organic substance 11 is dissolved may be applied onto the wafer 1 on which the resist pattern 2 is formed by a working step equivalent to the developing process. As a result, similarly to FIG. 2, the solution 11 permeates the holes 3 of the resist pattern 2 and the organic substance 3 is introduced.

After that, the wafer 1 immersed in the solution 11 is taken out from the solution 11. Alternatively, the solution 11 that has not penetrated into the resist pattern 2 out of the applied solution 11 is removed by slewing.

Through the above steps, the organic substance 11 is introduced into the pores 3 in the porous portion of the resist pattern 2, so that the deterioration of the etching resistance due to the resist pattern 2 being porous can be suppressed. That is, the etching resistance of the resist pattern 2 is improved. Further, it is clear that the presence of the organic matter 11 in the holes 3 can suppress the contraction due to the electron beam irradiation during the SEM observation.

Here, the organic substance 11 introduced into the holes 3 needs to be a low molecular weight so that it can easily penetrate into the porous portion of the resist pattern 2. Examples thereof include phenols. Specific examples thereof include phenol, hydroquinone, pyrogallol, cresol and the like as shown in FIG. 3 and isomers thereof. In particular, these substances contain a benzene ring and are known to have high etching resistance.

The concentration of the solution in which the organic substance 11 is melted may be 100% when the introduced substance itself is a liquid such as the above-mentioned phenols. Further, when it is necessary to dilute it for the purpose of ensuring work safety and reducing costs, it is possible to dilute up to about 10%. In this case, the diluent solvent is required to have a property of dissolving the organic substance 11 and not dissolving the resist pattern 2. Examples thereof include water, hexane, toluene, IPA and the like. Furthermore, the temperature of the solution is preferably higher on the permeation surface of the resist pattern 2, but may be about room temperature (about 25 ° C.) in consideration of ensuring safety of work and convenience.

As described above, the introduction of the organic substance 11 into the pores 3 is basically performed by the solution 10 permeating into the porous portion of the resist pattern 2 by the capillary phenomenon, and the time required for the permeation thereof is It takes about a few seconds. Therefore, the dipping time of the wafer 1 in the solution 10 (or the coating time of the solution 10 on the wafer 1) is about several seconds. However, within the takt time in various steps of the conventional photoengraving process, the processing capability of the entire photoengraving process does not decrease. Therefore, in order to stably obtain the effect of the present invention, there is no problem even if the immersion time of the wafer 1 in the solution 10 is about 1 minute.

When the resist pattern 2 has a large shape, it may be difficult to completely permeate the solution 10 into the resist pattern 2. However, the thickness of the resist consumed during etching is usually 200 to 400 nm, and thus sufficient effect can be obtained if the solution 10 penetrates from the surface to a depth equivalent to that.

Further, organic matter 1 is contained in the resist pattern 2.
In order to make it easier to introduce 1, the amount of residual solvent in the resist pattern after patterning may be increased. For example, the baking after the resist application and the baking after the exposure are performed at a low temperature within the range where the resolution is not deteriorated. The optimum baking temperature varies depending on the resist, but generally, even if the temperature is lowered by about 20 ° C., the resolution does not deteriorate.

Further, even if the resist film has a low porosity, there is almost no portion that is a perfect shield, and the resist film is porous to some extent. It is possible to introduce the organic matter even to a portion. Even in that case, a large amount of organic matter will be introduced into a portion having a high degree of porosity.

<Embodiment 2> As described above, by introducing the organic substance 11 into the holes 3 in the porous portion of the resist pattern 2, the etching resistance of the resist pattern 2 is improved, and at the time of SEM observation. Although shrinkage due to electron beam irradiation is also suppressed, the effect of improving the etching resistance of the resist pattern 2 is further enhanced by binding this organic substance to a polymer (resist polymer) which is a resist material.

Therefore, in the present embodiment, a cross-linking material is introduced into the pores of the porous portion of the resist pattern 2 together with the organic substance. An example of the cross-linking material is the melamine-based cross-linking material shown in FIG. By immersing the wafer 1 on which the resist pattern 2 is formed in the solution in which the cross-linking material and the organic material are dissolved (or applying the solvent to the wafer), the organic material and the cross-linking material are introduced into the holes of the resist pattern. To be done.

Here, the solvent in which the cross-linking material and the organic substance are dissolved is required to have the property of dissolving the organic substance 11 and not dissolving the resist pattern 2.
Examples include water, hexane, toluene, IPA and the like.

In this embodiment, the resist film forming the resist pattern is a chemically amplified resist. Since the chemically amplified resist contains an acid generator as a photosensitizer, it generates an acid when exposed to light. If the resist film is a negative type, the portion remaining as the resist pattern 2 is the exposed portion, and therefore the acid generated by the exposure remains therein. Due to the presence of the acid, bonds are formed between the organic material, the cross-linking material, and the resist polymer in the pores 3 of the resist pattern 2. FIG. 5 is a general formula of a chemical reaction (crosslinking reaction) associated with the bond. For example, the side chain of melamine bonds with a hydroxyl group in the presence of an acid as shown in this figure. Since a hydroxyl group and a carboxyl group are present in the resist and the phenolic organic substance introduced into the holes also has a hydroxyl group, it is possible to react with the cross-linking material.

FIG. 6 is a diagram schematically showing the state of the holes 3 in the resist pattern 2 after the reaction. In this figure, reference numeral 20 denotes a cross-linking material introduced into the pores 3 together with the organic substance 11, and the chemical reaction shown in FIG.
Bound to the polymer of the material. Due to this bonding, the etching resistance of the resist pattern 2 is further improved as compared with the case of the first embodiment.

In the present embodiment, when the resist film is a positive chemically amplified resist, the resist pattern 2 is formed by an unexposed portion, so that the resist pattern 2 diffuses from the exposed portion. Only traces of acid are present. Therefore, the crosslinking reaction may not proceed sufficiently. Therefore, in that case, after the resist pattern 2 is formed, an exposure process for generating an acid sufficient for the crosslinking reaction may be performed on the entire surface of the wafer.

<Third Embodiment> In this embodiment, the organic substance 11 introduced into the holes 3 of the resist pattern 2 and the resist polymer are bonded by EB (electron beam) irradiation. In this case, a cross-linking material is not necessary, and since the organic substance 11 does not necessarily have a hydroxyl group, there is an advantage that the choice of the organic substance 11 is widened.

Here, the resist polymer is decomposed and recombined by simply irradiating the resist pattern 2 with EB without introducing the organic substance 11 into the holes 3, thereby improving the etching resistance of the resist pattern 2. . However, the volume of the resist pattern decreases accordingly. In the present embodiment, the organic substances 11
The volume reduction is mitigated due to the presence of That is, it is possible to further improve the etching resistance as compared with the case of the first embodiment while suppressing the volume reduction of the resist pattern 2 due to the EB irradiation.

<Embodiment 4> In this embodiment, the organic substance 11 introduced into the holes 3 of the resist pattern 2 and the resist polymer are bonded by ion implantation.
In this case, the cross-linking material is unnecessary, and further, since the organic substance 11 does not necessarily have a hydroxyl group, the organic substance 11
Has the advantage of expanding the choices.

Here, the resist polymer is decomposed and recombined by simply implanting ions into the resist pattern 2 without introducing the organic substance 11 into the holes 3, thereby improving the etching resistance of the resist pattern 2. .
However, the volume of the resist pattern decreases accordingly. In the present embodiment, the organic substance 1
Due to the presence of 1, its volume reduction is mitigated. That is, it is possible to further improve the etching resistance as compared with the case of the first embodiment while suppressing the volume reduction of the resist pattern 2 due to the ion implantation.

<Embodiment 5> Depending on the combination of the organic material 11 and the resist material, the organic material 11 may be difficult to bond with the resist polymer. Therefore, in the present embodiment, a plurality of organic substances 11 introduced into one hole 3 are combined with each other to be polymerized.

As a method of coupling, for example, EB irradiation or ion implantation may be used. It is generally known that up to a molecular weight of about 10000, the higher the molecular weight, the higher the etching resistance becomes, and the organic substances 11 in the minute pores 3 are bonded to each other to be polymerized, and Etching resistance is improved. Thereby, the etching resistance of resist pattern 2 is further improved as compared with the case of the first embodiment.

At this time, the presence of the organic substance 11 in the holes 3 suppresses the volume reduction of the resist pattern due to EB irradiation or ion implantation.

<Embodiment 6> In Embodiment 1, as a process for introducing the organic substance 11 into the holes 3 of the resist pattern 2, a method of dipping the wafer in a solution of the organic substance 11 or the organic substance 11 on the wafer is used. The method of applying the solution of 1. That is, the liquid solution was brought into direct contact with the resist pattern 2.

However, when the solution of the organic substance 11 comes into contact with the resist pattern, it may be difficult to introduce the solution into the holes 3 due to the surface tension of the solution. Therefore, in the present embodiment, when organic substance 11 itself is a liquid in a normal state, it is evaporated and the wafer having resist pattern 2 formed thereon is exposed to the vapor. Thereby, the organic substance 11 can be efficiently introduced into the holes 3 of the resist pattern 2.

<Embodiment 7> In the present embodiment, a gas is used as a substance to be introduced into the holes 3. In this case, the organic matter includes methane and the like. Furthermore, CO
Inorganic substances such as 2 can also be targets of the substance to be introduced into the pores 3, and the choice of the substance to be introduced is widened.

As the introduction method, the wafer on which the resist pattern 2 is formed and the gas to be introduced are put in an airtight chamber,
Increase the pressure of the introduced gas. Thereby, the introduction substance is introduced into the holes 3.

As another method, it is possible to introduce an introduction substance into the chamber before the main etching in the etching process, and then to purge the introduction substance atmosphere and perform a normal etching process. According to this method, there is a limitation that only the pressure within the range used by the etcher can be applied, but there is an advantage that a special airtight chamber is unnecessary.

<Embodiment 8> In the present embodiment, a substance which contains carbon as an introduction substance and serves as an ion source is used, and the introduction substance is introduced into the holes 3 by ion implantation. As a substance containing carbon and serving as an ion source, there are carbon itself and carbon dioxide. Since carbon generally contributes to improving the etching resistance, the etching resistance of the resist pattern is improved thereby.

If it is necessary to further improve the etching resistance, EB irradiation or ion implantation may be further performed after the introduction of the introduction substance, as in the fifth embodiment. This strengthens the bond between the introduced material and the resist, and further improves the etching resistance.

<Embodiment 9> When the introduced substance is introduced into the holes 3 of the resist pattern 2, the volume of the resist pattern 2 naturally increases if the amount thereof is large. The amount of increase depends on the type and amount of the introduced substance. This is
It is suggested that the size of the resist pattern 2 can be adjusted by adjusting the type and amount of the introduced substance.

Therefore, in this embodiment, the size of the resist pattern is adjusted by adjusting the type and amount of the introduced substance. Although it is usually unnecessary to introduce the introduction substance in an amount larger than that required for improving the etching resistance into the holes 3, the amount and type of the introduction substance are determined for the purpose of adjusting the pattern size. This enables fine adjustment of the dimensions of the resist pattern 2. Therefore, it is possible to contribute to improvement of the dimensional accuracy of the resist pattern and the etching resolution.

For example, when the dimension is thinned by etching, it is effective to increase the dimension of the resist. This is particularly effective when forming fine holes.

It is needless to say that the present invention is not limited to the application to the resist pattern for ArF described above, but can be applied to any resist pattern having a porous structure and the same effect can be obtained. Yes.

[0063]

According to the resist pattern strengthening method of the first aspect of the present invention, (a) a step of forming a resist pattern on a wafer, and (b) a predetermined pattern containing at least carbon in the holes of the resist pattern. Since the step of introducing the introduced substance is provided, the etching resistance of the resist pattern is improved and the contraction during SEM observation is suppressed.

According to the resist pattern strengthening method of the second aspect, the resist pattern strengthening method of the first aspect, wherein the introduced substance is an organic substance, the step (b)
However, since the method includes the step of immersing the resist pattern in a solution of the organic material, the organic material is introduced into the holes of the resist pattern, the etching resistance of the resist pattern is improved, and the shrinkage during SEM observation is suppressed.

According to the resist pattern strengthening method of the third aspect, the resist pattern strengthening method of the first aspect, wherein the introduced substance is an organic substance, the step (b)
However, since the method includes the step of applying the organic material solution to the resist pattern, the organic material is introduced into the holes of the resist pattern, the etching resistance of the resist pattern is improved, and the shrinkage during SEM observation is suppressed.

According to the resist pattern strengthening method of claim 4, there is provided the resist pattern strengthening method of claim 2 or 3, wherein the resist pattern is
Formed by a chemically amplified resist, the step (a) is
Including the step of exposing the chemically amplified resist, the solution of the organic matter contains a cross-linking material that bonds the resist pattern and the organic matter using an acid as a catalyst, so the acid generated during exposure of the chemically amplified resist serves as a catalyst, As a result, the organic material and the resist pattern are combined. Therefore, the etching resistance of the resist pattern is further improved.

According to the resist pattern strengthening method of claim 5, there is provided the resist pattern strengthening method of claim 1, wherein the introduced substance is an organic substance, and the step (b)
However, since it includes a step of exposing the resist pattern to the vapor of an organic substance, the organic substance is introduced into the holes of the resist pattern,
While improving the etching resistance of the resist pattern,
Shrinkage during SEM observation is suppressed. In addition, compared with the case of directly applying the organic material solution, there is an advantage that the introduction substance is efficiently introduced in the step (b).

According to the resist pattern strengthening method of the sixth aspect, the resist pattern strengthening method according to any one of the second to fifth aspects is characterized in that the organic substance is a low molecular weight compound. It easily penetrates into the porous portion of the pattern, and organic substances are efficiently introduced into the pores.

According to the resist pattern strengthening method of the seventh aspect, the resist pattern strengthening method of any one of the second to sixth aspects is characterized in that the organic substance contains a benzene ring and has a high etching resistance. Since it is a high phenol, the etching resistance of the resist pattern is greatly improved.

The resist pattern strengthening method according to claim 8 is the resist pattern strengthening method according to claim 1, wherein the introduced substance is a gas of an organic substance or an inorganic carbon compound, and the step ( b) includes a step of raising the pressure of the gas after exposing the wafer on which the resist pattern is formed to a gas atmosphere, so that an organic substance is introduced into the holes of the resist pattern and the etching resistance of the resist pattern is improved, and Shrinkage during SEM observation is suppressed.

According to the resist pattern strengthening method of claim 9, there is provided the resist pattern strengthening method of claim 1, wherein the introduced substance is a substance serving as an ion source, and the step (b) is Since the step of ion-implanting the introduced substance into the resist pattern is included, the organic substance is introduced into the holes of the resist pattern by the ion implantation, the etching resistance of the resist pattern is improved, and the contraction during SEM observation is suppressed.

According to the resist pattern strengthening method of the tenth aspect, the resist pattern strengthening method according to any one of the first to ninth aspects further comprises:
(C) Since it includes the step of irradiating the resist pattern with an electron beam after the step (b), the bond between the introduced substance introduced into the holes of the resist pattern and the resist pattern, the bond between the introduced substances, and the resist. Recombination between the patterns occurs, and the etching resistance of the resist pattern is further improved. Further, the presence of the introduced substance in the holes reduces the volume reduction of the resist pattern due to the electron beam irradiation.

The resist pattern strengthening method according to claim 11 is the resist pattern strengthening method according to any one of claims 1 to 9, further comprising:
(D) Since it includes the step of performing ion implantation into the resist pattern after the step (b), the bond between the introduced material introduced into the holes of the resist pattern and the resist pattern, the bonding between the introduced materials, and the resist pattern Recombination of the two occurs, and the etching resistance of the resist pattern is further improved. Further, the presence of the introduced substance in the holes reduces the volume reduction of the resist pattern due to the ion implantation.

The resist pattern strengthening method according to claim 12 is the resist pattern strengthening method according to any one of claims 1 to 11, wherein the step (b) comprises By including the step of adjusting the dimension of the resist pattern by adjusting the amount and the amount, it is possible to finely adjust the dimension of the resist pattern. As a result, the dimensional accuracy of the resist pattern can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a step of immersing a wafer in a solution in which an organic substance is dissolved in the resist pattern strengthening method according to the first embodiment.

FIG. 2 is a schematic diagram showing a state in which an organic substance is introduced into the holes in the first embodiment.

FIG. 3 is a diagram showing an example of an organic substance used in the first embodiment.

FIG. 4 is a diagram showing an example of a cross-linking material used in the second embodiment.

FIG. 5 is a diagram showing a general formula of a crosslinking reaction in the second embodiment.

FIG. 6 is a diagram schematically showing a state of pores after a crosslinking reaction in the second embodiment.

FIG. 7 is a diagram showing an example of a conventional ArF resist material.

FIG. 8 is a diagram for explaining a problem of a conventional ArF resist.

FIG. 9 is a diagram for explaining a problem of a conventional ArF resist.

FIG. 10 is a diagram for explaining the relationship between resist dimensions and damage due to etching.

FIG. 11 is a diagram showing experimental data for comparing the amount of vacancies in an ArF resist and a KrF resist resist.

FIG. 12 is a diagram showing a change in the width of a resist depending on the number of times of SEM observation.

[Explanation of symbols]

1 wafer substrate, 2 resist pattern, 3 holes, 1
0 organic matter solution, 11 organic matter, 20 cross-linking material, 21
Bridge section.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA09 AB16 AC04 AC08 AD01                       BE00 CC20 FA33                 2H096 AA25 BA01 BA20 EA05 HA03                       HA05 JA04                 5F046 AA07 JA22

Claims (12)

[Claims] 1. A method of strengthening a porous resist pattern having holes inside, comprising: (a) forming the resist pattern on a wafer; and (b) at least forming holes in the resist pattern. And a step of introducing a predetermined introduced substance containing carbon. 2. The method of strengthening a resist pattern according to claim 1, wherein the introduced substance is an organic substance, and the step (b) includes a step of immersing the resist pattern in a solution of the organic substance. A method for strengthening a resist pattern, comprising: 3. The method for strengthening a resist pattern according to claim 1, wherein the introduced substance is an organic substance, and the step (b) includes a step of applying a solution of the organic substance to the resist pattern. A method for strengthening a resist pattern, comprising: 4. The method for strengthening a resist pattern according to claim 2, wherein the resist pattern is formed of a chemically amplified resist, and the step (a) comprises the step of forming the chemically amplified resist. A method of strengthening a resist pattern, comprising a step of exposing, wherein the solution of the organic material contains a cross-linking material which bonds the resist pattern and the organic material with an acid as a catalyst. 5. The method of strengthening a resist pattern according to claim 1, wherein the introduced substance is an organic substance, and the step (b) includes a step of exposing the resist pattern to vapor of the organic substance. A method for strengthening a resist pattern, comprising: 6. The method for strengthening a resist pattern according to claim 2, wherein the organic substance is a low molecule. 7. The method for strengthening a resist pattern according to claim 2, wherein the organic substance is a phenol. 8. The method for strengthening a resist pattern according to claim 1, wherein the introduced substance is a gas of an organic or inorganic carbon compound, and the resist pattern is formed in the step (b). A method of strengthening a resist pattern, comprising the step of increasing the pressure of the gas after exposing the wafer to the gas atmosphere. 9. The method for strengthening a resist pattern according to claim 1, wherein the introduced substance is a substance serving as an ion source, and the step (b) includes ion implantation of the introduced substance into the resist pattern. A method of strengthening a resist pattern, comprising: 10. The method for strengthening a resist pattern according to claim 1, further comprising: (c) performing electron beam irradiation on the resist pattern after the step (b). A method for strengthening a resist pattern, comprising the steps of: 11. The method for strengthening a resist pattern according to claim 1, further comprising: (d) performing the step (b) after the step (b) of implanting ions into the resist pattern. A method of strengthening a resist pattern, comprising the steps of: 12. The method of strengthening a resist pattern according to claim 1, wherein the step (b) adjusts the type and amount of the introduced substance to obtain the resist pattern. A method for strengthening a resist pattern, comprising the step of adjusting the dimension of the resist pattern.